The acoustic piano employs distinct and separate systems to transfer energy from a finger or actuator input force into an auditory, vibrational force. The transmission system, commonly called the action, is a network of levers, cushions and hammers which accept finger/actuator input force through a collection of pivotal levers, known as keys. The keys and action focus this input force into rotating hammers of proportional density which are positioned to strike against tensioned wire strings. Both hammers and their corresponding strings are carefully constructed to match their acoustic properties, resulting in a tapered or graduated “scale” of components which cumulatively produce a multiple note span of musical frequencies. The strings act as media through which vibrational energy is transferred into an amplifier such as a soundboard, or electric speaker, where it ultimately is converted into audible sound.
Pianos can produce a wide range of volume. Large pianos can further expand this range to include very loud sounds, as heard in concert pianos which are expected to broadcast over an orchestra without the assistance of electric amplification. Pianos are prevalent in many cultures worldwide. They are present in many households, schools, institutions etc. Inevitably, this proximity of volume producing instruments creates situations where sound control and reduction are necessary. Many piano manufacturers have provided muting mechanisms within the piano to selectively restrict its volume level. These mechanisms typically include a rotating rail which inserts an impact-absorbing material of varying density between the hammers and strings. One conventional (prior art) mute rail system 10, as shown in FIG. 1, includes a key 1, an action 2 with a hammer 3 and a tensioned string 4. Suspended above the action 2 is a mute rail 5 which rotates around a pivot point 6 to place an absorbent material 7 between the hammer 3 and string 4. This type of mute rail reduces the piano volume to a level of sound calculated to avoid disruption of neighboring environments such as apartments, practice rooms, etc.
Other conventional (prior art) systems, such as the mute rail system 20 shown in FIG. 2, are often excessively flexible due to the limited number of anchor points that are available for a rail 22 mounted within the interior of the action space. These systems can exhibit excessive vibratory motion when struck by groups of hammers at high velocities. The excessive vibratory motion dampens rebound forces of the hammers after impact, thereby changing the tactile sensation of the rebound forces as felt in the keys by the musician. The distance between the mute rail system 20 and the strings is also generally greater due to deflection of the mute rail system 20, than otherwise, resulting in a comprise of the original, acoustical mode adjustment of the action.
Conventional mute rail systems often require ample space within the confined action cavity, in order to achieve their full rotation. The extra space is achieved along a vertical, horizontal, or depth axis, creating challenges for installation, structural stability, and long term performance consistency.